Abstract:

A lighting system may include a substrate and a light emitting device
(LED) on the substrate, and the light emitting device may be configured
to transmit light having a first wavelength along a path away from the
substrate. A remote reflector may be spaced apart from the light emitting
device, and the light emitting device may be between the substrate and
the remote reflector. The remote reflector may also be in the path of the
light having the first wavelength transmitted by light emitting device. A
luminescent layer may be on a surface of the remote reflector, and the
luminescent layer may be configured to convert a portion of the light
having the first wavelength to light having a second wavelength different
than the first wavelength. Moreover, the remote reflector may be
configured to reflect light having the first and second wavelengths.

Claims:

1. A lighting system comprising:a light emitting device (LED) configured
to transmit light having a first wavelength along a path;a remote
reflector spaced apart from the light emitting device wherein the remote
reflector is in the path of the light having the first wavelength
transmitted by light emitting device; anda luminescent layer on a surface
of the remote reflector, wherein the luminescent layer is configured to
convert a portion of the light having the first wavelength to light
having a second wavelength different than the first wavelength, and
wherein the remote reflector is configured to reflect light having the
first and second wavelengths.

2. A lighting system according to claim 1 further comprising:a second
light emitting device (LED) configured to transmit light having a third
wavelength different than the first and second wavelengths along a path,
wherein the remote reflector is spaced apart from the first and second
light emitting devices, and wherein the remote reflector is in the path
of the light having the third wavelength transmitted by the second light
emitting device.

3. A lighting system according to claim 2 wherein the remote reflector is
configured to reflect light having the first, second, and third
wavelengths.

4. A lighting system according to claim 1 wherein the remote reflector
includes a reflective surface on an opaque support member.

5. A lighting system according to claim 4 wherein the reflective surface
comprises a metallic layer.

6. A lighting system according to claim 5 wherein the metallic layer
comprises a layer of silver and/or aluminum.

7. A lighting system according to claim 1 wherein the luminescent layer
comprises a phosphor material in a translucent and/or transparent binder
agent.

8. A lighting system according to claim 7 wherein the binder agent
comprises a silicone, an epoxy, and/or a plastic.

10. A lighting system according to claim 1 wherein the remote reflector
comprises a concave reflector surface configured to focus the reflected
light having the first and second wavelengths.

11. A lighting system according to claim 1 wherein the light emitting
device is spaced apart from the reflector surface and from the
luminescent layer by a distance of at least about 1 cm.

12. A lighting system according to claim 1 wherein the light emitting
device is spaced apart from the reflector surface and from the
luminescent layer by a distance of at least about 10 cm.

13. A lighting system according to claim 1 further comprising:a housing
reflector surrounding the light emitting device wherein the housing
reflector is spaced apart from the remote reflector.

14. A lighting system according to claim 1 further comprising:a second
light emitting device configured to transmit light having the first
wavelength along a path toward the luminescent layer and the remote
reflector.

15. A lighting system according to claim 1 further comprising:a substrate
wherein the light emitting device (LED) is on the substrate and wherein
the light emitting device is between the substrate and the remote
reflector.

16. A lighting system comprising:a light emitting device (LED) configured
to transmit light having a first wavelength along a path;a remote
reflector spaced apart from the light emitting device wherein the remote
reflector is in the path of the light having the first wavelength
transmitted by light emitting device; anda luminescent layer on a surface
of the remote reflector, wherein the luminescent layer is configured to
convert a portion of the light having the first wavelength to light
having a second wavelength different than the first wavelength, wherein
the remote reflector is configured to reflect light having the first and
second wavelengths and wherein the light emitting device is spaced apart
from the reflector surface and from the luminescent layer by a distance
of at least about 1 cm.

17. A lighting system according to claim 16 further comprising:a
substrate, wherein the light emitting device is on the substrate such
that the light emitting device is between the substrate and the remote
reflector.

18. A lighting system according to claim 16 further comprising:a second
light emitting device (LED) configured to transmit light having a third
wavelength different than the first and second wavelengths, wherein the
remote reflector is spaced apart from the first and second light emitting
devices, and wherein the remote reflector is in a path of the light
having the third wavelength transmitted by the second light emitting
device.

19. A lighting system according to claim 16 wherein the light emitting
device is spaced apart from the reflector surface and from the
luminescent layer by a distance of at least about 10 cm.

20. A lighting system according to claim 16 further comprising:a housing
reflector around the light emitting device and wherein the housing
reflector is spaced apart from the remote reflector.

21. A lighting system according to claim 16 further comprising:a second
light emitting device adjacent the first light emitting device wherein
the second light emitting device is configured to transmit light having
the first wavelength along a path toward the luminescent layer and the
remote reflector.

22. A lighting system comprising:a light emitting device (LED) configured
to transmit light having a first wavelength along a path;a housing
reflector adjacent the light emitting device;a remote reflector spaced
apart from the light emitting device and from the housing reflector,
wherein the remote reflector is in the path of the light having the first
wavelength transmitted by light emitting device; anda luminescent layer
on a surface of the remote reflector, wherein the luminescent layer is
between the remote reflector and the housing reflector and between the
remote reflector and the light emitting device, wherein the luminescent
layer is configured to convert a portion of the light having the first
wavelength to light having a second wavelength different than the first
wavelength, and wherein the remote reflector is configured to reflect
light having the first and second wavelengths.

23. A lighting system according to claim 22 further comprising:a
substrate, wherein the light emitting device and the housing reflector
are on the substrate between the substrate and the luminescent layer.

24. A lighting system according to claim 22 wherein the light emitting
device is spaced apart from the reflector surface and from the
luminescent layer by a distance of at least about 1 cm.

25. A lighting system according to claim 22 wherein the light emitting
device is spaced apart from the reflector surface and from the
luminescent layer by a distance of at least about 10 cm.

Description:

FIELD OF THE INVENTION

[0001]The present invention relates to the field of lighting, and more
particularly, to LED lighting systems, reflectors, and methods.

BACKGROUND

[0002]An incandescent bulb, including a wire filament encased in glass,
may emit only about 5% of the energy it consumes as light, with the
remaining 95% percent of the energy being wasted as heat. Fluorescent
lights may be approximately 4 times more efficient than incandescent
bulbs, but may include toxic materials such as mercury vapor. Light
emitting diodes may generate light as efficiently as fluorescent lights
without the toxic mercury vapor. Light emitting diodes are thus being
developed for lighting applications to replace incandescent bulbs and
fluorescent lights as discussed, for example, in the article entitled "An
Even Brighter Idea" from The Economist Print Edition, Sep. 21, 2006.

[0003]U.S. Patent Publication No. 2006/0056169 entitled "Light Module
Using LED Clusters" (the '169 publication), for example, discusses a
streetlight wherein the conventional incandescent light bulb is replaced
by sets of light-emitting LED clusters. In the '169 publication, light
emitting diodes are mounted in a downward direction in a manner to
disperse light directly onto the intended area of the road or street
surface.

[0005]According to some embodiments of the present invention, a lighting
system may include a substrate and a light emitting device (LED) on the
substrate, and the light emitting device may be configured to transmit
light having a first wavelength along a path away from the substrate. A
remote reflector may be spaced apart from the light emitting device such
that the light emitting device is between the substrate and the remote
reflector and such that the remote reflector is in the path of the light
having the first wavelength transmitted by light emitting device. A
luminescent layer on a surface of the remote reflector may be configured
to convert a portion of the light having the first wavelength to light
having a second wavelength different than the first wavelength, and the
remote reflector may be configured to reflect light having the first and
second wavelengths. For example, the light having the first wavelength of
light may be a blue light, and the light having the second wavelength of
light may be a yellow light.

[0006]In addition, a second light emitting device (LED) may be configured
to transmit light having a third wavelength different than the first and
second wavelengths along a path away from the substrate, and the remote
reflector may be spaced apart from the first and second light emitting
devices. Moreover, the remote reflector may be in the path of the light
having the third wavelength transmitted by the second light emitting
device, and the remote reflector may be configured to reflect light
having the first, second, and third wavelengths. For example, the light
having the first wavelength of light may be a blue light, the light
having the second wavelength of light may be a yellow light, and the
light having the third wavelength of light may be a red light.

[0007]The remote reflector may include a reflective surface on an opaque
support member, and the reflective surface may include a metallic layer
such as a layer of silver and/or aluminum. The luminescent layer may
include a phosphor material in a translucent and/or transparent binder
agent, and the binder agent may include a silicone, an epoxy, and/or a
plastic. The phosphor material may include a yttrium-aluminum-garnet
(YAG) phosphor material, an oxynitride phosphor material, a nitride
phosphor material, and/or a zinc oxide phosphor material.

[0008]The remote reflector may have a concave reflector surface configured
to focus the reflected light having the first and second wavelengths.
Moreover, the light emitting device may be spaced apart from the
reflector surface and from the luminescent layer by a distance of at
least about 1 cm, and more particularly, by a distance of at least about
10 cm.

[0009]In addition, a housing reflector on the substrate may surround the
light emitting device, and the housing reflector may be spaced apart from
the remote reflector. A second light emitting device may also be provided
on the substrate, and the second light emitting device may be configured
to transmit light having the first wavelength along a path away from the
substrate and toward the luminescent layer and the remote reflector. In a
street light application, for example, the light emitting device may be
spaced apart from the reflector surface and from the luminescent layer by
a distance of at least about 1 meter, and more particularly, by a
distance in the range of about 2 meters to about 3 meters. A spacing of
the light emitting device from the reflector surface and/or from the
luminescent layer may be a function of, for example, a size of the
reflector surface, a curvature of the reflector surface, an area being
illuminated, and/or a distance from the reflector to the area being
illuminated.

[0010]According to other embodiments of the present invention, a lighting
system may include a light emitting device (LED) configured to transmit
light having a first wavelength along a path. A remote reflector may be
spaced apart from the light emitting device in the path of the light
having the first wavelength transmitted by light emitting device. A
luminescent layer on a surface of the remote reflector may be configured
to convert a portion of the light having the first wavelength to light
having a second wavelength different than the first wavelength. Moreover,
the remote reflector may be configured to reflect light having the first
and second wavelengths, and the light emitting device may be spaced apart
from the reflector surface and from the luminescent layer by a distance
of at least about 1 cm. For example, the light having the first
wavelength of light may be a blue light, and the light having the second
wavelength of light may be a yellow light.

[0011]The light emitting device may be provided on a substrate such that
the light emitting device is between the substrate and the remote
reflector. In addition, a second light emitting device (LED) may be
configured to transmit light having a third wavelength different than the
first and second wavelengths. The remote reflector may be spaced apart
from the first and second light emitting devices, and the remote
reflector may be in a path of the light having the third wavelength
transmitted by the second light emitting device. Accordingly, the remote
reflector may be configured to reflect light having the first, second,
and third wavelengths. For example, the light having the first wavelength
of light may be a blue light, the light having the second wavelength of
light may be a yellow light, and the light having the third wavelength of
light may be a red light.

[0012]The remote reflector may include a reflective surface on an opaque
support member, and the reflective surface may include a metallic layer
such as a layer of silver and/or aluminum. The luminescent layer may
include a phosphor material in a translucent and/or transparent binder
agent, and the binder agent may include a silicone, an epoxy, and/or a
plastic. The phosphor material may include a yttrium-aluminum-garnet
(YAG) phosphor material, an oxynitride phosphor material, a nitride
phosphor material, and/or a zinc oxide phosphor material.

[0013]The remote reflector may have a concave reflector surface configured
to focus the reflected light having the first and second wavelengths, and
the light emitting device may be spaced apart from the reflector surface
and from the luminescent layer by a distance of at least about 10 cm. In
addition, a housing reflector may be provided around the light emitting
device, and the housing reflector may be spaced apart from the remote
reflector. A second light emitting device adjacent the first light
emitting device may also be configured to transmit light having the first
wavelength along a path toward the luminescent layer and the remote
reflector.

[0014]According to still other embodiments of the present invention, a
lighting system may include a light emitting device (LED) configured to
transmit light having a first wavelength along a path and a housing
reflector adjacent the light emitting device. A remote reflector may be
spaced apart from the light emitting device and from the housing
reflector, and the remote reflector may be in the path of the light
having the first wavelength transmitted by light emitting device. A
luminescent layer may be provided on a surface of the remote reflector
between the remote reflector and the housing reflector and between the
remote reflector and the light emitting device. The luminescent layer may
be configured to convert a portion of the light having the first
wavelength to light having a second wavelength different than the first
wavelength, and the remote reflector may be configured to reflect light
having the first and second wavelengths. For example, the light having
the first wavelength of light may be a blue light, and the light having
the second wavelength of light may be a yellow light.

[0015]In addition, the light emitting device and the housing reflector may
be provided on a substrate between the substrate and the luminescent
layer. The remote reflector may include a reflective surface on an opaque
support member, and the reflective surface include a metallic layer such
as a layer of silver and/or aluminum. The luminescent layer may include a
phosphor material in a translucent and/or transparent binder agent, and
the binder agent may include a silicone, an epoxy, and/or a plastic. The
phosphor material may include a yttrium-aluminum-garnet (YAG) phosphor
material, an oxynitride phosphor material, a nitride phosphor material,
and/or a zinc oxide phosphor material.

[0016]The remote reflector may include a concave reflector surface
configured to focus the reflected light having the first and second
wavelengths. The light emitting device may be spaced apart from the
reflector surface and from the luminescent layer by a distance of at
least about 1 cm, and more particularly, by a distance of at least about
10 cm. In a street light application, for example, the light emitting
device may be spaced apart from the reflector surface and from the
luminescent layer by a distance of at least about 1 meter, and more
particularly, by a distance in the range of about 2 meters to about 3
meters. A spacing of the light emitting device from the reflector surface
and/or from the luminescent layer may be a function of, for example, a
size of the reflector surface, a curvature of the reflector surface, an
area being illuminated, and/or a distance from the reflector to the area
being illuminated.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a cross-sectional view of lighting systems according to
embodiments of the present invention.

[0018]FIG. 2 is an enlarged cross-sectional view of a reflector with a
luminescent layer thereon according to embodiments of the present
invention.

[0019]FIG. 3 is an enlarged plan view of a substrate with a housing
reflector and light emitting devices thereon according to embodiments of
the present invention.

[0020]FIGS. 4A and 4B are perspective views illustrating remote reflectors
having concave shapes according to embodiments of the present invention.

DETAILED DESCRIPTION

[0021]Embodiments of the present invention now will be described more
fully hereinafter with reference to the accompanying drawings, in which
embodiments of the invention are shown. This invention may, however, be
embodied in many different forms and should not be construed as limited
to the embodiments set forth herein. Rather, these embodiments are
provided so that this disclosure will be thorough and complete, and will
fully convey the scope of the invention to those skilled in the art. Like
numbers refer to like elements throughout. Dimensions of layers,
elements, and structures may be exaggerated for clarity.

[0022]It will be understood that, although the terms first, second, etc.
may be used herein to describe various elements, these elements should
not be limited by these terms. These terms are only used to distinguish
one element from another. For example, a first element could be termed a
second element, and, similarly, a second element could be termed a first
element, without departing from the scope of the present invention. As
used herein, the term "and/or" includes any and all combinations of one
or more of the associated listed items.

[0023]It will be understood that when an element such as a layer, region
or substrate is referred to as being "on" or extending "onto" another
element, it can be directly on or extend directly onto the other element
or intervening elements may also be present. In contrast, when an element
is referred to as being "directly on" or extending "directly onto"
another element, there are no intervening elements present. It will also
be understood that when an element is referred to as being "connected" or
"coupled" to another element, it can be directly connected or coupled to
the other element or intervening elements may be present. In contrast,
when an element is referred to as being "directly connected" or "directly
coupled" to another element, there are no intervening elements present.

[0024]Relative terms such as "below" or "above" or "upper" or "lower" or
"horizontal" or "vertical" may be used herein to describe a relationship
of one element, layer or region to another element, layer or region as
illustrated in the figures. It will be understood that these terms are
intended to encompass different orientations of the device in addition to
the orientation depicted in the figures.

[0025]The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of the
invention. As used herein, the singular forms "a", "an" and "the" are
intended to include the plural forms as well, unless the context clearly
indicates otherwise. It will be further understood that the terms
"comprises," "comprising," "includes" and/or "including" when used
herein, specify the presence of stated features, integers, steps,
operations, elements, and/or components, but do not preclude the presence
or addition of one or more other features, integers, steps, operations,
elements, components, and/or groups thereof.

[0026]Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which this invention
belongs. It will be further understood that terms used herein should be
interpreted as having a meaning that is consistent with their meaning in
the context of this specification and the relevant art and will not be
interpreted in an idealized or overly formal sense unless expressly so
defined herein.

[0027]Various embodiments of the present invention including semiconductor
light emitting devices will be described herein. As used herein, the term
semiconductor light emitting device (LED) may include a light emitting
diode, laser diode and/or other semiconductor device which includes one
or more semiconductor layers, which may include silicon, silicon carbide,
gallium nitride, indium gallium nitride, and/or other semiconductor
materials. A light emitting device may or may not include a substrate
such as a sapphire, silicon, silicon carbide and/or another
microelectronic substrates. A light emitting device may include one or
more contact layers which may include metal and/or other conductive
layers. In some embodiments, ultraviolet, blue and/or green light
emitting diodes may be provided. Red, red-orange, and/or amber LEDs may
also be provided. The design and fabrication of semiconductor light
emitting devices are well known to those having skill in the art and need
not be described in detail herein.

[0028]For example, semiconductor light emitting devices (LEDs) discussed
herein may be gallium nitride-based LEDs or lasers fabricated on a
silicon carbide substrate such as those devices manufactured and sold by
Cree, Inc. of Durham, N.C. The present invention may be suitable for use
with LEDs and/or lasers as described in U.S. Pat. Nos. 6,201,262;
6,187,606; 6,120,600; 5,912,477; 5,739,554; 5,631,190; 5,604,135;
5,523,589; 5,416,342; 5,393,993; 5,338,944; 5,210,051; 5,027,168;
4,966,862 and/or 4,918,497, the disclosures of which are incorporated
herein by reference as if set forth fully herein. Other suitable LEDs
and/or lasers are described in published U.S. Patent Publication No. US
2003/0006418 A1 entitled Group III Nitride Based Light Emitting Diode
Structures With a Quantum Well and Superlattice, Group III Nitride Based
Quantum Well Structures and Group III Nitride Based Superlattice
Structures, published Jan. 9, 2003, as well as published U.S. Patent
Publication No. US 2002/0123164 A1 entitled Light Emitting Diodes
Including Modifications for Light Extraction and Manufacturing Methods
Therefor, the disclosures of which are hereby incorporated herein in
their entirety by reference. Furthermore, phosphor coated LEDs, such as
those described in U.S. Patent Publication No. 2004/0056260 A1, entitled
Phosphor-Coated Light Emitting Diodes Including Tapered Sidewalls and
Fabrication Methods Therefor, the disclosure of which is incorporated by
reference herein as if set forth fully, may also be suitable for use in
embodiments of the present invention. The LEDs and/or lasers may be
configured to operate such that light emission occurs through the
substrate. In such embodiments, the substrate may be patterned so as to
enhance light output of the devices as is described, for example, in the
above-cited U.S. Patent Publication No. US 2002/0123164 A1.

[0029]Referring to the embodiments of FIGS. 1 and 3, substrate 103 (also
referred to as a submount) may include a printed circuit board (PCB)
substrate, an aluminum block substrate, an alumina substrate, an aluminum
nitride substrate, a sapphire substrate, and/or a silicon substrate,
and/or any other suitable substrate material, such as a T-Clad thermal
clad insulated substrate material, available from The Bergquist Company
of Chanhassen, Minn. A PCB substrate may include standard FR-4 PCB, a
metal-core PCB, flex tape, and/or any other type of printed circuit
board.

[0030]According to some embodiments of the present invention, a lighting
system may include a plurality of light emitting devices (LEDs) 101a-c
mounted on a substrate 103 and surrounded by a housing reflector 105 on
the substrate 103 as shown in FIG. 1. Moreover, each of the light
emitting devices (LEDs) 101a-c may be configured to transmit light along
a respective path(s) 115 away from the substrate. As further shown in
FIG. 1, a remote reflector 107 may be spaced apart from the light
emitting devices 101a-c, and the light emitting devices 101a-c may be
between the substrate 103 and the remote reflector 107. Moreover, the
remote reflector 107 may be in the path(s) 115 of the light transmitted
by the light emitting devices 101a-c.

[0031]At least one of the light emitting devices 101a-c may be configured
to transmit light having a first wavelength, and a luminescent layer 109
may be provided on a surface of the remote reflector 107. More
particularly, the luminescent layer 109 may be configured to convert a
portion of the light having the first wavelength to light having a second
wavelength different than the first wavelength, and the remote reflector
107 may be configured to reflect light having the first and second
wavelengths. For example, the light emitting device 101a may be
configured to transmit blue light, and the luminescent layer 109 may
include a yellow phosphor so that yellow light from the yellow phosphor
and blue light from the light emitting device 101a reflect off the remote
reflector 107 and combine in the target direction 117 to provide white
light transmitted in the target direction 117.

[0032]The luminescent layer 109 may thus be remote from the light emitting
device(s) 101a-c so that the luminescent layer 109 and the light emitting
device(s) 101a-c are separated, for example, by a gap filled with gas, a
vacuum gap, and/or a light transmissive material (such as glass). By
providing the luminescent layer 109 on the remote reflector 107,
separated from the light emitting device(s) 101a-c and from the housing
reflector 105, an efficiency of transmission/reflection of the light
having the second wavelength (i.e., light converted by the luminescent
layer 109) in the target direction 117 may be improved.

[0033]While a plurality of light emitting devices 101a-c are shown in FIG.
1 by way of example, embodiments of the present invention may be provided
with only a single light emitting device transmitting light having the
first wavelength (such as LED 101a transmitting blue light). If a second
light emitting device (such as LED 101b) is included, the second light
emitting device 101b may be configured to transmit light having a third
wavelength different than the first and second wavelengths along a path
away from the substrate 103. With first and second light emitting devices
101a-b transmitting different wavelengths of light, the remote reflector
107 is in the path(s) 115 of the light transmitted by the first and
second light emitting devices 101a-b. Accordingly, the remote reflector
is 107 is configured to reflect light having the first, second, and third
wavelengths in the target direction 117.

[0034]For example, the light emitting device 101a may be configured to
transmit blue light, and the luminescent layer 109 may include a yellow
phosphor so that white light is reflected off the reflector 107 in the
target direction 117 as discussed above. In addition, the light emitting
device 101b may be configured to transmit red light that is reflected off
the reflector 107 in the target direction to provide "warmth" to the
white light provided by combining the blue and yellow light. Moreover,
multiple blue light emitting devices and/or multiple red light emitting
devices may be provided to increase an intensity of blue and/or red light
transmitted to the luminescent layer 109 and the reflector 107, and/or
light emitting devices configured to transmit light of other colors
(wavelengths) may be provided in addition to or instead of blue and/or
red. In addition, the luminescent layer 109 may include phosphors
generating light having a color(s) other than yellow and/or the
luminescent layer 109 may include a plurality of different phosphors
generating a plurality of different colors.

[0035]A third light emitting device (such as LED 101c) on the substrate
103, for example, may be configured to transmit light having the first
wavelength along a path away from the substrate 103 and toward the
luminescent layer 109 and the remote reflector 107. While three light
emitting devices are shown in FIG. 1 by way of example, any number of
light emitting devices may be used. For example, only a single light
emitting device transmitting light having the first wavelength may be
used. Moreover, multiple light emitting devices transmitting the first
wavelength may be used to increase an intensity of light of the first and
second wavelengths. In addition or in an alternative, one or more light
emitting devices may be provided transmitting light having a
wavelength(s) different than the first wavelength.

[0036]As shown in FIG. 1, the housing reflector 101 may be provided on the
substrate 103 surrounding the light emitting devices 101a-c, and inner
surfaces of the housing reflector 101 may be angled to direct light from
the light emitting devices 101a-c toward the remote reflector 107.
Moreover, the housing reflector 105 may be spaced apart from the remote
reflector 107 and from the luminescent layer 109 as shown in FIG. 1.

[0037]An enlarged plan view (taken from a direction of the reflector 107
back toward the light emitting devices 101a-c) of the housing reflector
105 and light emitting devices 101a-c on the substrate 103 according to
some embodiments of the present invention is provided in FIG. 3. As shown
in FIG. 3, the housing reflector 105 may surround the light emitting
devices, and additional light emitting devices 101d-e (not shown in the
cross-section of FIG. 1) may be included. The substrate 103 may include
electrical couplings between the light emitting devices 101a-e and a
power source(s) on the substrate 103 and/or on the support structure 111.
The substrate 103, for example, may include a printed circuit board.

[0038]While the path(s) 115 of light transmitted by the light emitting
devices 101a-c are illustrated in FIG. 1 as being substantially
perpendicular with respect to the substrate 103, it will be understood
that each of the light emitting devices 101a-c may transmit light in a
hemispheric or quasi-hemispheric pattern from directions substantially
parallel with respect to the substrate 103 to directions substantially
perpendicular with respect to the substrate 103 and directions
therebetween. By providing the housing reflector 105, more light from the
light emitting devices 101a-c may be directed to the remote reflector 107
to direct more light more efficiently in the target direction(s) 117 and
to reduce potential light emission in other directions, which may be
wasted and/or otherwise undesired (e.g., as light pollution). Moreover, a
height of the housing reflector 105 relative to the substrate 103 may be
greater than a height of the light emitting devices 101a-c relative to
the substrate 103 to reduce loss of light and/or light pollution in a
direction parallel to a surface of the substrate 103.

[0039]According to some embodiments of the present invention, the housing
reflector 105 and the substrate 103 may be separately formed and then
assembled, and/or the housing reflector 105 may be formed on the
substrate 103. According to other embodiments of the present invention,
the housing reflector 105 and the substrate 103 may be formed together as
a single unit. According to still other embodiments of the present
invention, the substrate 103 may be provided as a part of the support
structure 111. According to yet other embodiments of the present
invention, the housing reflector 105 may be omitted, and/or the light
emitting devices 101a-c may be provided in recesses of the substrate 103.

[0040]As further shown in FIG. 1, a support structure 111 may be used to
maintain a desired orientation of the substrate 103 and light emitting
devices 101a-c thereon relative to the remote reflector 107. Moreover,
the support structure 111 may be configured to maintain the remote
reflector 107 and the light emitting devices 101a-c in an orientation to
direct light reflected from the remote reflector 107 in a target
direction(s) 117. A coupling between the remote reflector 107 and the
support structure 111 and/or a coupling between the substrate 103 and the
support structure 111 may be adjustable to provide different target
direction(s) 117 and/or to provide a wider or narrower focus of light
transmitted in the target direction(s) 117. The support structure 111,
for example, may include a pole of a street light to elevate the remote
reflector 107 10 feet or more off the ground, a base of a lamp to elevate
the remote reflector 107 one to three feet off a table or desk, a base of
a pole lamp to elevate the remote reflector 107 4 to 7 feet off a floor.
According to other embodiments of the present invention, the structure of
FIG. 1 may be configured to provide track lighting so that the support
structure 111 is mounted to a ceiling or a wall with the target direction
117 directed down (for direct lighting), up (for indirect lighting), or
any direction therebetween.

[0041]As shown in FIG. 2, the remote reflector 107 may include a
reflective surface 121 on an opaque support member 123, and the
luminescent layer 109 may be provided on the reflective surface 121. More
particularly, the reflective surface 121 may include a metallic layer,
such as a layer of silver and/or aluminum. The luminescent layer 109 may
include a phosphor material in a translucent and/or transparent binder
agent. More particularly, the binder agent may include a silicone, an
epoxy, and/or a plastic, and the phosphor material may include a
yttrium-aluminum-garnet (YAG) phosphor material, an oxynitride phosphor
material, a nitride phosphor material, and/or a zinc oxide phosphor
material. According to some embodiments of the present invention, the
luminescent layer 109 may include YAG and red phosphors. The support
member 123 may be "optically black" so that any light transmitted through
the reflective surface 121 may be blocked from transmission through the
support member 107.

[0042]As shown in FIGS. 1 and 2, the remote reflector 107 may have a
concave reflector surface configured to focus the reflected light having
the first and second wavelengths. With a concave shape, portions of the
concave reflector surface may be symmetric about a point (for example,
providing a spheroidal, paraboloidal, and/or hyperboloidal shape) and/or
portions of the concave reflector surface may be symmetric about a line
(for example, providing a cylindrical shape). While concave reflectors
are discussed by way of example, the remote reflector 107 may have other
reflector surface shapes (such as flat and/or convex) according to other
embodiments of the present invention.

[0043]Examples of remote reflector shapes are illustrated in FIGS. 4A and
4B. FIG. 4A illustrates a remote reflector 107' (including support member
123' and reflective surface 121') with a luminescent layer 109' thereon,
wherein the remote reflector 107' has a shape that is symmetric about a
line (such as a cylindrical shape). FIG. 4B illustrates a remote
reflector 107'' (including support member 123'' and reflective surface
121'') with a luminescent layer 109'' thereon, wherein the remote
reflector 107'' has a shape that is symmetric about a point (such as a
spheriodal shape.) The support members, reflective surfaces, and
luminescent layers of FIGS. 4A and 4B may be provided as discussed above
with respect to FIGS. 1 and 2. Moreover, the reflector 107 of FIG. 1 may
be provided having shapes as illustrated for example in FIG. 4A or FIG.
4B, or the reflector 107 of FIG. 1 may be provided having other shapes.

[0044]While not shown in FIG. 1, the light emitting devices 101a-c, the
housing reflector 105, the remote reflector 107, and/or the luminescent
layer 109 and/or portions thereof may be shielded and/or protected from
an external environment. For example, an encapsulant such as a
transparent epoxy, plastic, and/or silicone layer may be provided on the
light emitting devices 101a-c and/or on the housing reflector 105. In
addition or in an alternative, the light emitting devices 101a-c, the
housing reflector 105, the luminescent layer, and the remote mirror 107
may be enclosed with a transparent window allowing transmission of the
output light in the target direction 117.

[0045]According to embodiments of the present invention, structures
illustrated in FIGS. 1 and 2 may be scaled in size to provide lighting
systems for different applications. For example, the light emitting
device(s) 101a-c may be spaced apart from the reflector surface 107 and
from the luminescent layer 109 by a distance (e.g., in a direction along
light path(s) 115) in the range of about 1 cm to about 10 cm or greater
in a desk lamp. In an alternative, the light emitting device(s) 101a-c
may be spaced apart from the reflector surface 107 and from the
luminescent layer 109 by a distance in the range of about 10 cm to about
300 cm or greater in a street light. With a greater separation between
the light emitting device(s) 101a-c and the remote reflector 107, a
reflective surface area of the remote reflector may increase. In a street
light application, for example, the light emitting device may be spaced
apart from the reflector surface and from the luminescent layer by a
distance of at least about 1 meter, and more particularly, by a distance
in the range of about 2 meters to about 3 meters. A spacing of the light
emitting device from the reflector surface and/or from the luminescent
layer may be a function of, for example, a size of the reflector surface,
a curvature of the reflector surface, an area being illuminated, and/or a
distance from the reflector to the area being illuminated.

[0046]While not shown in FIG. 2, the remote reflector 107 may include one
or more additional layers such as a diffusion layer, a scattering layer,
and/or a clear protective layer. A diffusion and/or a scattering layer
may be provided between the luminescent layer 109 and the reflective
surface 121, and/or on the luminescent layer 109 opposite the reflective
surface 121. A protective layer may be provided on the luminescent layer
109 opposite the reflective surface 121.

[0047]In the drawings and specification, there have been disclosed typical
embodiments of the invention and, although specific terms are employed,
they are used in a generic and descriptive sense only and not for
purposes of limitation, the scope of the invention being set forth in the
following claims.